This invention relates generally to electrical control systems, and more specifically relates to an electrical connector for aircraft fuel pumps.
A conventional electrical connector 10 for aircraft fuel pumps is illustrated in FIG. 1. The electrical connector includes a cup-shaped connector shell 12 with an outer radial connector flange 14 approximately 0.080 inch thick, and a glass electrical insulating plug 16 mounted in the cup-shaped connector shell. A plurality of connector pins 18 are mounted in the glass insulating plug, each having a portion 20 extending from the glass insulating plug and covered by potting 22, such as an epoxy resin potting compound, for example. Electrical cables (not shown) would also extend through the potting to the individual connector pins.
In aircraft, electrical arcing in the presence of a fuel leak can lead to disastrous results. Airworthiness Directive (AD 97-03-17) issued following reports of fuel leaks at the fuel boost and override/jettison pumps, and electrical arcing that occurred on JAL 747 aircraft, which resulted from formation of a conductive layer between potting of the connector and electrical insulation glass of the connector. The conductive layer provided an electrical path for arcing to occur between connector pins, or between one or more connector pins and the casing of the connector, which was severe enough to burn through the connector shell, allowing fuel to leak to the environmental side of the fuel pump. The potting of the connector formed an imperfect seal with the connector, and contributed to the severity of the arcing condition by allowing contamination to become trapped in the connector, which initiated arcing. In addition, the potting of the connector contained the arcing event, allowing extreme heat and pressure to build up. Subsequent carbonization of the potting provided a conductive path for the arc and provided additional material to sustain the arcing reaction which could burn through surrounding material to permit a fuel leak to occur.
It would therefore be desirable to provide an improved, non-potted open design for an electrical connector for aircraft fuel pumps, allowing potential contaminants to escape or be removed from the electrical connector. It would also be desirable to provide an improved electrical connector for aircraft fuel pumps with an improved glass hermetic seal, connector flange and electrical insulating risers to provide electrical insulation and an increased current leakage path between each pin of the connector and between the connector pins and the connector housing. It would also be desirable to provide strain relief and improved electrical insulation of the electrical connector. There, thus exists a need for an improved electrical connector for fuel pumps, particularly for aircraft. The present invention addresses these and other concerns.